Problem Details

Minecraft v1.12.2
Forge v14.23.5.2838
Better Chesting v1.1.1
Metal Transport v2.1.1

I got this crash after trying to combine a chest with items in it (made possible with Better Chesting) with a minecart in the crafting screen of my player. I'm not sure if the it's because of this mod or if it's related to Better Chesting though.

Crash Report

Presently, I see no information that the problem is w/ MetalTransport. If, when you tried to crafting the resulting minecart w/ chest, got a valid output, that means my recipe was registered properly. That's only crafting interaction I have. Based on the log it seems the problem is w/ the Placebo library. If you go into Placebo's config file there should be an option to disable "fast recipes." Set that to false and see if things work out.

I reported it to Placebo first at Shadows-of-Fire/Placebo#4, but the mod author said it wasn't related to his mod. The output also didn't appear before crashing.

I can try disabling the "fast recipes" option later though.

I'm not able to reproduce this crash anymore, so hopefully it's fixed.
Although if I right-click a Minecart with a chest with items in it, the items are lost.
It might be something that needs compatibility added for.

It will need to be yes. The dev of better chesting can add compat through my robust api, which will have more docs after some more profiles are added in.